About 15 years ago, I worked on code that delivered working versions to customers, repeatedly, who used it an reported zero bugs. It simply did what it was meant to, what had been agreed, from the moment they started using it.
The key was this: "the requirements are polished and any questions answered by stakeholders"
We simply knew precisely what we were meant to be creating before we started creating it. I wonder to what degree the magic of "spec driven development" as you call it is just that, and using Claude code or some other similar is actually just the expression of being forced to understand and express clearly just what you actually want to create (compared to the much more prevalent model of just making things in the general direction and seeing how it goes).
The key was this: "the requirements are polished and any questions answered by stakeholders"
We simply knew precisely what we were meant to be creating before we started creating it. I wonder to what degree the magic of "spec driven development" as you call it is just that, and using Claude code or some other similar is actually just the expression of being forced to understand and express clearly just what you actually want to create (compared to the much more prevalent model of just making things in the general direction and seeing how it goes).